下扬子地区分区走时表及计算机查表实用程序的编制

一般地震走时表是由一定间隔震中距查算各震相走时。本文所介绍的根据P与S波走时差值由计算机实时快速编制和查算区域地震走时表的方法和程序,适用于震源在壳内任意深度,可含低速层的水平均匀分层模型。此外,本文还给出了下扬子三个分区、三种深度的走时表,以供没有计算机的台站或地震现场作精细定位之用。

TABULATION OF SEISMIC TRAVELTIMES FORTUREE SUBREGIONS IN THE LOWER YANGTZEAREA AND A UTILITY PROGRAM WRITING FORTRAVELTIME REFERENCE ON COMPUTERS

Seismic traveltimes are generally determined by consulting a traveltime table tabulated in reference to the distances from an epicenter. This paper suggests to regionally tabulated seis- mic traveltimes in real time on computers in terms of the traveltime difference betwen P and S waves, so that seismic traveltimes can be rapidly determined by a program running in com- puters. The method for traveltime tabulation and reference introduced in the paper is suita- ble for horizontally stratified homogeneous models which are allowable to include low ve- locity zones and sources buried at arbitrary depths. The paper also provides the traveltime talbes of three depths which are applicable for pre- cise positioning in three subregions in the lower Yangtze area in consideration of the cases when no computer is available at some observation stations or investigation sites.